Pressure is mounting on House Republican leaders to form a special committee to investigate the September attack on the U.S. consulate in Benghazi, Libya, that resulted in the death of U.S. Ambassador Christopher Stevens.

Proponents of a special panel maintain that the five committee chairmen currently leading the House GOP’s ongoing Benghazi investigation are too concerned with protecting their turf.

Rep. Frank R. Wolf, R-Va., has been calling for the House to create a bipartisan special committee to investigate the Benghazi attack since November. Wolf introduced a resolution earlier this year which has attracted 134 GOP co-sponsors, including 14 who signed on last month immediately after the release of a progress report on the current investigation. Five more co-sponsors signed on this week. No Democrats support the bill.

Even so, it doesn’t appear that Speaker John A. Boehner or the committee chairmen feel enough heat to abandon their opposition to a special panel. “The speaker has confidence in the chairmen, members and staff at the committees of jurisdiction,” Boehner spokesman Michael Steel said Thursday.

Supporters of the existing investigatory framework argue privately that a special committee would have to start from scratch, impeding the goal of getting to the bottom of what happened.

The current Republican-led investigation, launched shortly after the incident on Sept. 11, is a joint effort of the Armed Services, Judiciary, Intelligence, Foreign Affairs, and Oversight and Government Reform committees. Their initial disclosure directly implicates former Secretary of State Hillary Rodham Clinton as culpable in the terrorist attack. Democrats have accused Republicans of playing politics.

Supporters of creating a special committee still weren’t satisfied. Their calls for such a body have increased since Fox News reported this week that President Barack Obama's administration has blocked government officials who want to testify about Benghazi from using whistle-blower protections. The Fox News report also said that military help might have been available to respond to the Benghazi attack, had the administration ordered it.

The incident occurred at the height of the 2012 presidential campaign, and Republicans have suggested that the administration wanted to downplay the event for political purposes.

Wolf continues to field calls from relatives of those killed in Benghazi, according to his spokeswoman, Jill Shatzen, reinforcing his determination to continue pushing for the creation of a special committee. Wolf's office contends that formation of a special panel does not require House adoption of Wolf's resolution, just a decision by Boehner. But aides familiar with House rules told CQ Roll Call that the chamber would have to vote to create a special committee, at least one that had a dedicated staff and subpoena power.

Wolf maintains that a special committee would not have to start from scratch, but could use information uncovered by the current joint-committee investigation. He says creating the elevated panel is the only way to shine a light on what happened in Benghazi.

Former Rep. Allen B. West, R-Fla., who retains some influence inside the conservative grass roots, announced Thursday that he also supports creating a special committee.

“What the five committees are doing is not sufficient,” Shatzen said. The House chairmen in question include Armed Services' Howard "Buck" McKeon and Foreign Affairs' Ed Royce, both of California; Intelligence's Mike Rogers of Michigan; Judiciary's Robert W. Goodlatte of Virginia and Oversight and Government Reform's Darrell Issa of California.

Also dissatisfied is Senate Armed Services ranking member, John McCain of Arizona.

McCain said he would prefer that Boehner and Senate Majority Leader Harry Reid, D-Nev., form a bipartisan, bicameral special committee to investigate what happened in Benghazi. But conceding that Reid is unlikely to join such an effort, McCain is urging Boehner to launch a special committee in the House, and is blaming the five committee chairmen for being instrumental in blocking such a move.

"Harry Reid will not agree to it. If it has to be the House of Representatives, God speed," McCain told conservative talk show host Hugh Hewitt. "I would like to see the pressure, pressure on Harry Reid to make it a real joint committee, because I think some of us have to, have things to contribute. But if it has to be in the House, fine with me, but let’s get going,"

"We’ve got to have a little straight talk here," McCain added. "Some of the people that are resisting it are the committee chairmen who see that they would be losing some of their areas of responsibility."